"Sex for me is ... perhaps the single greatest humanizing force on this earth," Hugh Hefner said during a 1974 interview with CBS, sitting alongside Protestant theologian Harvey Cox. "It would be a rather sad planet if there weren't two sexes. And I think that we've managed to use and abuse and misunderstand our sexuality."

"Sex is cheap," sociologist Mark Regnerus at the University of Texas at Austin, explains in his book, "Cheap Sex: The Transformation of Men, Marriage and Monogamy. "It is more widely available, at lower cost to all than ever before in human history. ... Cheap sex has been mass-produced with the help of two distinctive means that have little to do with each other -- the wide uptake of the Pill and mass-produced high-quality pornography -- and then made more efficient by communication technologies. They drive the cost of sex down, make real commitment more 'expensive' and challenging to navigate, ... put women's fertility at risk -- driving up demand for infertility treatments -- and have taken a toll on men's marriageability ... Cheap sex does not make marriage unappealing; it just makes marriage less urgent and more difficult to accomplish."

Playboy was certainly on the cutting edge of the sexual revolution, albeit in ways that seem relatively quaint compared to what's taken as convention these days. Regnerus opens the book with the story of a 32-year-old named Sarah, who is essentially looking for love in all the wrong places, so to speak. Adrift in a sea of casual relationships, she still wants marriage someday -- only nothing she's doing is likely to get her there, as Regnerus' research makes clear.

And his is no "wistful" ode to an era that never was, but a clear-eyed look at what's going on. Regnerus writes with compassion about Sarah and other woman in the U.S. "mating market." His chronicle of the situation, based on extensive numbers and interviews, shows what misery the Playboy Philosophy, as it were, has wrought. It's one fueled by medicine -- primarily, birth control -- and an ideological idolization of a false freedom that changed not just mores, but expectations and led to utter incoherence in individual lives.

"Despite shrinking double standards and growing egalitarianism, something seems amiss with sex these days," Regnerus writes. "Most Americans -- left or right, religious or not -- can sense it. ... Online porn is now standard operating procedure for a near-majority of men. We construct comprehensive identities and communities around sexual attraction in a way unfamiliar to most of the Western world, including Western Europe. Cultural struggles over marriage continue -- now out of the political limelight -- in households, congregations and workplaces. Meanwhile, the common date has eroded, now quaint in light of the ubiquitous, unromantic hookup. ... We can't seem to get enough of sex -- so we focus on technique -- but what we get is leaving us hungering for still more or longing for some emotion or transcendent satisfaction that cheap sex seems to promise but seldom delivers. Social and interpersonal trust erodes; solitude and atomization increase. Mothers and fathers split. In light of these common realities, how many of us would confidently declare that yes, these are the best of times in American sexuality, that we are making progress, that we have modeled a template of more satisfying, fulfilling sexual unions?"

Hugh Hefner has been quoted talking about the devastation of infidelity -- his first wife cheated on him. He also said, during that CBS interview, "I think that there are certain aspects of adolescence that might be best retained for a lifetime." Pretending this is a healthy attitude would fall on the immature side of our perpetual adolescent times and would mean we've learned nothing from Hefner's life and legacy. Hefner's passing invites us to get moving on next steps, so love won't be lost more permanently -- out of reach for so many -- to a state of misery pretending to be freedom.